the Trustee postal scale, U.S.A.
This Trustee postal scale was made by The Eastern Metalcraft Co., from Waterbury in Connecticut. It is a typical American letter scale with a lot of postal rate information on the scale front. The scale is subdivided per half ounce and weighs up to 16 ounces. the postal letter rate of 3c per ounce was valid in the period 1917-1919 and in the period 1932-1958. The air mail rate of 6c per ounce was valid from December 15, 1918 until 1919 and from 1934 until 1944 and again from 1949 until 1955. The Zone rate for Air Mail Parcel Post of 55c for zones 1&2 and 60c for zone 3, and 65c for zone 4 -this all for the first 1Lb.-, was valid from 1948 until 1950. This postal scale would therefore be dated in the short period of 1948-1950.
At the measurement scale bottom right is printed: Pat. Pending. A patent application would have been made. A search provided indeed a patent: US patent 2,588,322 filed April 16, 1948 and granted only on March 4, 1952. This confirms the proper short period of this postal scale is 1948-1950.
Below are the figures of the patent. The patent describes a cheap to manufacture, high quality letter scale, with a special spring nut to easily adjust the tension spring and fine-tune the scale.
At the side is a sticker of Heiman & Churnin, Inc. This was a printing and stationary in New York who sold this postal scale.
Below some more pictures of the Trustee postal scale.
the scale obliquely from behind
